Revert of Allow use of Mojo/V8 ProxyResolvers with URLRequestContextBuilder.

net/proxy/test_mojo_proxy_resolver_factory.cc

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "net/proxy/test_mojo_proxy_resolver_factory.h"
-
-#include "base/memory/ptr_util.h"
-#include "mojo/public/cpp/bindings/strong_binding.h"
-#include "net/proxy/mojo_proxy_resolver_factory_impl.h"
-
-namespace net {
-
-TestMojoProxyResolverFactory* TestMojoProxyResolverFactory::GetInstance() {
-  return base::Singleton<TestMojoProxyResolverFactory>::get();
-}
-
-std::unique_ptr<base::ScopedClosureRunner>
-TestMojoProxyResolverFactory::CreateResolver(
-    const std::string& pac_script,
-    mojo::InterfaceRequest<interfaces::ProxyResolver> req,
-    interfaces::ProxyResolverFactoryRequestClientPtr client) {
-  resolver_created_ = true;
-  factory_->CreateResolver(pac_script, std::move(req), std::move(client));
-  return nullptr;
-}
-
-TestMojoProxyResolverFactory::TestMojoProxyResolverFactory() {
-  mojo::MakeStrongBinding(base::MakeUnique<MojoProxyResolverFactoryImpl>(),
-                          mojo::MakeRequest(&factory_));
-}
-
-TestMojoProxyResolverFactory::~TestMojoProxyResolverFactory() = default;
-
-}  // namespace net